Methan gas dissolved in water can be used to grow bacteris, which degrade chlori
ID: 1920098 • Letter: M
Question
Methan gas dissolved in water can be used to grow bacteris, which degrade chlorinated solvents.
A) if each gram of methane can produce 0.7g of cabteris, calculate the mass of bacteris thhat could be produced from 1L of water. The water was initially exposed to 25 percent methane in air in a pressure of 1 atm. After equilibration, it was isolated from furthur gas-phase contact.
B) Will there be enough dissolved oxygen in the water for all the methane to ne stociometrically oxidized? assume that some of the methane is fully oxidized to H2O and CO2. The effective chemical formulafor new bacterial cells is C5H2NO2. Assume a sufficient quantity of nitrogen is dissolved in the water so that it is not limiting.
Answer both questions with steps to solve it (to recieve full pts)
Explanation / Answer
A) from henrys law
p=K*c
p is partial pressure of methane in air , p=0.25*1=.25
K is henry constant, K=666.67 atm/M for methane
c= 0.25/666.67 =3.75*10^-4 M
moles of methane/vol of water = 3.75*10^-4 M
no of moles of methane = 3.75*10^-4 *1 moles
mass of methane = 3.75*16*10^-4 =6*10^-3 g
mass of bacteria from 1L of water = 0.7*6*10^-3 =4.2 * 10^-3 gm
B)mole fraction of oxygen in air = 0.75*0.2 = 0.15
K for O2 = 769.23
c of O2 = 0.15*1/769.23 =1.95*10^-4 M
moles of O2 = 1.95*10^-4
CH4+O2--->CO2+2H2O
no there wont be enough O2
as there are 37.5 milli moles of methane of which only 19.5 millimoles are Oxidised by 19.5 milli moles of O2 desolved